Adjustable two layered screen for hammer mills and remote control therefor



ET AL REEN F AND REMOTE CONTROL Filed March 23,

2,440,927 OR HAMMER MILLS THEREFOR 1945 4, 1948- F. BOSS ADJUSTABLE TWO LAYERED SC INVENTORLF.

Patented May 4?, 1 948 2,440,927 ADJUSTABLE TWO LAYERED SCREEN FOR HAMMER MILLS THEREFOR AND REMOTE CONTROL Floris Boss and Earl Nemic, Grand Rapids, Mich.- Application March 23, 1945, Serial No. 584,418,

8 Claims.

This invention relates to improvements in adjustable two layered screen for hammer mills and remote control therefor.

The main objects of this invention are:

First, to provide a grinding mill of the hammer type for grinding feed and the like with ascreen which is adapted for remote control adjustment through a wide range.

Second, to provide a screen for grinding machines which is not likely to become clogged.

Third, to provide a screen having these advantages which maybe installed in or embodied in grinding mills, particularly hammer mills, of types now in quite extensive use.

Fourth, to provide a structure having these advantages which is very compact.

Objects relating to details and economies of the invention will appear from the description to follow. The invention is defined and pointed out in the claims. 1

A preferred embodiment of the invention is illustrated in th accompanying drawing, in which: 7

Fig. l is a fragmentary view partially in vertical sectionof a grinding mill or machine of the hammer type embodying the invention, certain of the parts being shown conventionally.

Fig. 2 is an enlarged fragmentary view mainly in section on line 22 of Fig. 1.

Fig. 3 is a fragmentaryplan view of the screen in one position of adjustment, namely, fully open position.

Fig. 4 is a fragmentary plan view of the screen with the screen members adjusted to an intermediate position of adjustment.

Fig. 5 is a fragmentary plan view with the screen members adjusted to the extreme position I of adjustment.

In Figs. 3, 4 and 5, the screen members are shown in the flat instead of being arcuate as shown in Fig. 1.

In the accompanying drawing, the housing I is mainly-conventionalized and is provided with a grain feed chute 2, a discharge chamber 3 communicating at 4 with the blower conventionally indicated at 5 and having a discharge conduit 6. The rotor l is provided with hammers 8. All of these are shown mainly in conventional form and the details thereof form no part of our present invention.

In the embodimentof the invention illustrated, the screen designated generally by the numeral 9 constitutes a part of the wall of the housing and a partition between the milling chamber and the discharge chamber 3. This screen comprises her but closely associated therewith so that it has a wiping action as it is adjustedthereon, thus becoming clogged.-

preventing the screen from These members I0 and metal of suitable gauge sponding or aligned rows ing, in the preferred embodiment illustrated, relatively large apertures I l4, there being in the embodiment illustrated two of the small apertures l4 between each adjacent pair of large apertures. In each of the rows extending in the direction of adjustment of the slidable screen member H a large aperturealternates with two smallapertures, with both small apertures being longitudinally aligned in the row. The large apertures of adjacent rows-are-staggered and the rows of apertures are spacedles's than the diameter of H are formed of sheet when in'certain positions of adjustment the large apertures overlap or large apertures of adjacent rows, see Fig. 5.

In Fig. 3, the screen members are adjusted so that all of the apertures register thus pro-' viding a screen having both large and small aper-' tures, the small apertures serving to increase the capacity of the screen so the small particles'can pass therethrough.

Fig. 4 shows the screen members adjusted so that the large apertures of corresponding rows of the two screen members are in partial register, thus cutting down the size of the apertures.

In Fig. 5, the screen members are shown in their extreme position of adjustment so that the screen apertures consist of certain of the small apertures M which register centrally with the large apertures I 3 and with certain other small apertures M of the two screen members register-' ing with each other, there still being some overlap or register of- I sponding rows, the large apertures however partially registering or overlapping with two of the large apertures of the adjacent rows, thus form ing a screen 'made up of apertures I l and 15'" resulting from the coaction of the 'twoscreen members. This is the maximum adjustment for fine screening but it will of course be apparent that the size of the openings may be varied. Very satisfactoryresults, however, 'maybe had when L It is preferably sup with the fixed mem and both have c0rreof apertures compris-' 3 and small aperturesthe large apertures so that- 'partially registerwith the the large apertures of correby the drag link 23 I The segment is preferably provided with indicia positions of adjustment in ,the adjusting lever being 22. The other arm of the rockshaft is connected with the slidable screen H.

to indicate the adjusted position, there being five the device illustrated, in the fourth position as shown in the drawing. It is obvious that there might be any desired number (if adjustments but ordinarily five positions are deemed suflicient.

We are aware that mills of this type have been provided with adjustable screens, one being shown for example in the Hughes Patent; 2,227,090 in which the screen is adjusted lateraliy, the screen having three sections of different mesh. Other structures have been provided with interchangeable screens; Qne of the main objects of our invehtion' is to provide a simple screen structure which has a wide range of adjustment, is compact; and may be adjusted by remote control. The im portanee of this will be understood when it is appreciatcdthat these mills are largely so-e-alled custom mills-that is, they grind relatively small batches of grain and succeeding customers very commonly require that the grain be ground to dilfo'rent degrees of fineness.

We have illustrated and described our invention in an embodiment which we consider very practical: We have not attempted to illustrate ordeseribe other embodiments or adaptations as it is believed that this disclosure will enable those skilled in the art to embody or adapt our invention as may be desired.

Having thus descrbed our invention, what we chimes new and desire to secure by Letters Patents; V

1; m is grinding machine having a housing and a grinding member operatively. mounted in the housing, a screen comprising relatively fixed and rotatably arcuate members, each having a plurality of rows of relatively large apertures and relatively small apertures in the rows between the large apertures, there being a plurality oi-sm'ali apertures between each pair of large apertures, the large apertures of adjacent-rows being staggered, the rows of apertures being spaced less than the diameter or the large apertures, means for slidably supporting the slidable screen member through such mange of ad jus'tment that the apertures of the-two members may he brought into register and so that the large apertures of adjacent rows may be brought into overlapping relation and certain of the small apertures of one screen member cent-rally positinned relative to the large apertures of the other screen membm'anfi means rorselectively adjustlng said 'slidable seree member.

2. In a grinding machine having a housing and a minding member bperativeiy mounted in the a cbmphising relatively fixed and I rosemary sesame arcuate members, each member mung-a plurality of rows of relatively large sapertarss and relatively small apertures in the dows b'etween the large apertures, the large a ertures or ia'dcacenit staggered, the

apertures spaced less 'sthan-the-diameter of the large apertures, and means for slidably supporting the slidable screen member, said rows of large apertures in each screen member being disposed parallel to the direction of slidable movement of the slidable screen member, two small apertures alternating with a single large aperture in each row, said two small apertures being aligned longitudinally of the row, said large and small apertures being so spaced relative to each other in rows and the range of slidable adjustment of the slidable screen member being such that the apertures of the two screen members may be brought into substantial register and so that the large apertures of adjacent rows may be brought into overlapping partial registering relation and certain or the small apertures of one screen member are in register with the large apertures of the other screen member and simultaneously therewith certain other small apertures in one screen member are in register with certain other small apertures in the other screen member.

3. In a grinding machine of the rotatable hammer type having a housing wherein the hammers are rotatably mounted; of -a discharge chamber associated with said housing, a screen between said housing and discharge chamber comprising relatively fixed and slidable arcuate members, each member having a plurality of'rows of relatively large apertures, the apertures of adjacent rows being staggeredand the rows of apertures being spaced so that they may be brought into partialoverlapping relation, said screen members having a plurality-of small apertures aligned in the rows with the large apertures, a large aperture and a plurality of small apertures alternating in each row and aligned longitudinally of the row, and means for adjusting the slidable screen member, said plurality of rows being parallel to the path of adjustment of said slidable member, the range of adjustment and the relative spacing of the large and small apertures being such that the corresponding large apertures of the rows may be brought into register or into partial overlapping relation with the large apertures of adjacent rows and such that certain small apertures may be brought into register with large apertures and simultaneously therewith certain other small apertures brought into register with each other.

4. In a, grinding machine having a housing and a grinding member opera 'v cly mounted in the housing, a discharge screen for said housing comprising ar-cuate relatively fixed and .slidable members, each member having rows of relatively large and relatively small apertures, the large apertures of the adjacent rows being staggered, the large apertures and the small apertin' es being relatively spaced in the members so that the large .apertures of corresponding rows may be brought into register or into partial overlapping register with the large apertures of'adjacent rows and with certain of the small apertures of one membercentrally registering with the large apertures of the other member, and simultaneously therewith certain othersmal l apertures of the members registering with each other, and means for adjustably supporting the slidabie member :in a plurality of selected positions of adjustment.

5. In a grinding machine having a housing and a grinding member operatively mounted in the housing, a discharge screen rfor said housing comprising arcuate relatively .fixedyand 'slidable members, each membcrlhaving rows of relatively large and relatively small apertures, :the large apertures of the adjacent rows being staggered, the

large apertures and the small apertures being relatively spaced in the members so that the large apertures of corresponding rows may be brought into register or into partial overlapping register with the large apertures of adjacent rows and so that certain small apertures are in register with large apertures and simultaneously therewith certain other small apertures are in register with each other, and means for adjustably supporting the slidable member in a plurality of selected positions of adjustment.

6. In a grinding machine, the combination with a housing and a grinding member mounted within the housing, of a discharge screen for said housing comprising arcuate relatively fixed and slidable members, each having corresponding aligned rows of apertures, each row having relatively large and relatively small apertures therein, the larger apertures of adjacent rows being staggered and the rows of apertures being spaced so that the large aperture of one row may be brought into partial overlapping register with the large aperture of the adjacent rows, the small apertures being spaced in the rows relative to the large apertures so that when the apertures of adjacent rows are in overlapping position certain of the small apertures of corresponding rows are in register with large apertures thereof, supporting rollers for the edges of the slidable screen member, an adjusting means for said slidable screen member comprising a hand lever, a coacting detent segment provided with indicia, and operating connections for said hand lever to said slidable screen.

7. In a grinding machine, the combination with a housing and a grinding member mounted within the housing, of a discharge screen for said housing comprising arcuate relatively fixed and slidable members, each having corresponding aligned rows of apertures, each row having relatively large and relatively small apertures therein, the larger apertures of adjacent rows being staggered and the rows of apertures being spaced so that the large aperture of one row may be brought into partial overlapping register with the large apertures of the adjacent rows, the small apertures being spaced in the rows relative to the large apertures so that when the apertures of adjacent rows are in overlapping position certain of the small apertures of corresponding rows are in register with large apertures thereof and so that simultaneously therewith certain other small apertures are in register with each other, and means for adjusting said slidable member.

8. In a grinding machine, the combination with a housing and a grinding member mounted within the housing, of a discharge screen for said housing comprising arcuate relatively fixed and rotatably slidable members, each having corresponding aligned rows of apertures, the apertures of adjacent rows being staggered and the rows of apertures being spaced so that the aperture of one row may be brought into partial overlapping register wtih the apertures of the adjacent rows, sup- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Y Name Date 632,362 Page Sept. 5, 1899 729,883 Mood et al June 2, 1903 818,725 Williams Apr. 24, 1906 908,618 Skagen Jan. 5, 1909 1,634,026 Fritz June 28, 1947 1,839,532 Calhoun Jan. 5, 1932 2,227,090 Hughes Dec. 31, 1940 FOREIGN PATENTS Number Country Date 11,825 Great Britain of 1909 442,051 Germany v Mar. 21, 1947 

